<i>Mega Man II</i> was where the Mega Man games we all know and love started to take shape. With a full compliment of 8 powerful robots, including:
<b><i>Bubble Man</b></i> - In an underwater level, shoots bubbles and plasma shots at you while swins around. Watch out for the spikes on the ceiling.
<b><i>Air Man</b></i> - Air Man shoots 3 tornadoes from one side of the screen to the other. Some you can dodge, others not.
<b><i>Quick Man</b></i> - As his name suggests, Quick Man is FAST. He jumps and runs at lightspeed shooting boomerangs at you. An uneven floor makes him difficult to dodge, too.
<b><i>Wood Man</b></i> - Uses leaves as him main weapon. He'll create a spinning shield of leaves and throw it at you, then leaves fall from the top of the screen.
<b><i>Flash Man</b></i> - Flash man doesn't have much of an active weapon, he stops time momentarily and shoots a rapid-fire plasma cannon at you. The slippery floors don't help with your dodging, either.
<b><i>Heat Man</b></i> - Looking like a giant pissed off Zippo lighter, Heat Man attacks in two ways. He will either throw fireballs which make flames rise from the ground, or he will turn himself into fire and charge you.
<b><i>Crash Man</b></i> - Crash Man is kind of difficult to beat, it takes timing and a Energy Canister or two. When you fire your weapon (even if not at him) he will jump in the air and throw bombs at you. You need to time your attacks to hit him when he jumps.
<b><i>Metal Man</b></i> - Metal Man is not too difficult to beat. He will be on the opposite side of the room, jumping up and down and throwing up to three sawblades at you at a time. The floor is also a conveyor belt, making movement and dodging difficult.
This game is one of the best in the Mega Man series. Featuring two levels of difficulty and challenging levels, it'll keep you entertained. Also this game introduced bonus items Item-1, Item-2, and Item-3. One climbed walls, one made a rocket (very useful in Heat Mans stage), and the other made a balloon. Dr. Wily's levels and bosses were also very challenging and fun.
Music, once again, was excellent, especially in Metal Man and Crash Mans stage.
I consider this game to be the first true Mega Man game, it set the standard for all its descendants. I rate Mega Man II an 8 out of 10.
Like you I consider MM2 to be where the greatness truly took off. As I stated in the MM1 review thread, the first game set the groundwork and was fun, but was extremely rough and had a fair share of flaws. Heck it didn't even have a password system.
2 is where they honed their design skills down to perfection. Notable is they cleaned up a number of rather glaring glitch issues from the previous game, and "flicker" is almost gone, excepting when those chainsaw drill thingies are filling the screen.
The bosses here are all very unique, with their own movement patterns and with moves that work in very different ways. Every level has a well established theme to it with clever design that serves to further distinguish the levels from one another. There's no recycling here. Further, aside from enemies fated to become future mascots like the helmet heads (yes I know they are "met-als" but I've called them helmet heads since I was a kid and I sticks by that), each level has it's own distinct baddies that act in distinct ways, such as giant fish spitting out shrimp and frogs in Bubble Man's stage, or bats, wolves and rabbits in Wood Man's stage, or those notorious insta-death beams that make you have to move quick in Quick Man's stage.
The weapons are great fun, from freezing time around you, to crash bombs latching onto things and exploding, to quick boomerangs, to a shield made of leaves (that surprisingly actually worked) to a charged shot of atomic fire, to the single greatest thing ever, the metal blade. It fires in all directions, is as powerful as you would expect a giant spinning buzzsaw/gear thing to be, and uses ridiculously little weapon energy (you have to fire a few shots just to remove one bar of it). Plus, it's just COOOOOL. Heck, it's so unbalanced that instead of one boss is weak against one specific weapon, it's more like 5 or so bosses are weak against this thing. As a rule, if all else fails, use metal blades. It's great against wood man (if you lack atomic fire), bubble man, and even metal man, the guy you get them from. Heck he dies in two shots of the thing!
The music is even better than the original and really set the standard. There's a reason there's so many remixes of the songs from this game. Metal Man's music is, as one might expect, effin' metal. Odin himself couldn't have done better.
Visually, everything is nicely distinguished. In this game they redesigned the weapon and life powerups (they kinda look more "mechanical" now) which they stuck with for the rest of the NES games, and the Gameboy games. Bubble Man's stage is full of rushing water and little bubbles floating about. Metal Man's stage has gears rotating in the background, and that sort of thing. They make good use of both side scrolling and vertical regions to give a good mix. One thing notable is I never noticed until I read about it years later that many NES games couldn't scroll in two directions simultaneously, they had to pick either horizontal or vertical and stick with it. The games that could had to use an expantion chip to give the NES that capability, like SMB3. Good games managed to hide this weakness well, and this game certainly managed it.
Wily's Fortress was a much more fun experience than before. The mood setter that did a lot to help things was showing the actual fortress from the outside before you set foot in it. That lovely bleeping as the game shows "you are here" and your plotted destination gave a sense of real progress through the castle. It's funny because you get to a skull at the end and think it's the end, but then a SECOND skull appears and there's the actual end. As an extra note, at some point Mega Man's path splits and reconnects, and in my head I always just imagine Bugs Bunny's ears above water and them splitting apart to go around some obstacle, and then imagining Megaman did something like that. As an aside that fortress. looked so very much like one of those massive playsets for a Saturday morning cartoon, like the Cobra Headquarters headquarters, or the Shredder's "Technodrome", or the Thundercats giant cat base thingy. You can almost see the music suddenly winding down and Wily going to the back to change the AA batteries to start it back up again. Heck I always wondered why Mattel or some other enterprising toy company never cornered the rights to that and released a "Wily's Castle" playset. They'll probably only get around to it when a Megaman movie comes out down the line.
The castle stages really felt epic, right from the start with that thundering extremely frantic music. Right away you're attacked by birds and their eggs and have to use a special item just to get started getting over huge millitary bunkers in your way. From there it just goes up and up and suddenly a DRAGON is CHASING you. You know it's a boss but you're just concerned with running away as it knocks blocks out from behind you. The second stage has a barrage of spike pits you have to use the rocket sled over and the end level is the boss room itself, as the wall starts coming apart, forming together and rushing after you. Guts Man is rebuilt as a massive tank, and then there's the horrible 4th stage boss of a series of... I don't even know how to describe them, THINGS on the wall firing weird energy balls at you. The mood of that stage, and the music, seems to be of "strange technology" and it certainly isn't anything I as a kid had seen before. The problem is so many of these stages relied on limited-ammo items just to get through. If you die, get ready to refill your precious subweapon of necessity. Those bizarre whatits on the wall in stage 4 are notorious for only being damagable by crash bombs, absolutely everything else just bounces off. However, you don't have enough ammo to destroy both the walls in front of them all AND all of them. If you ration carefully, it IS possible, if you never miss, to take out ONLY the absolutely necessary walls AND all the wall turret thingies, but when you first try it? You won't know that, and you'll end up having to kill yourself. Fortunatly, the walls stay "dead" so you run back in, the walls are gone, and if you refilled your weapon energy, you can destroy them all rather easily now.
Instead of having a few robot masters fight you at certain points along the wily stages, this time you have to fight them all at the very end, picking them from teleporter tubes, not knowing what leads to who the first time but eventually memorizing this. After this, you face down Wily's machine. As a kid, I remember the image of that thing filling me with dread, it was just terrifying to look at that massive thing floating on-screen and firing non-stop massive bolts of energy at weird curving angles. The whole thing just looked so completely alien, and beating it only knocked off it's armor plating. The gears underneath just made it look even more scary and it fired those bouncing energy balls even more in a new pattern. When you finally win, you think it's over but no, he flies off. Welcome to the final stage. With all that cool music they go for a very cool mood-setting change, total silence. You're just falling, falling down a hole deep underground, who knows where? When you hit the ground, the only thing you hear now is the drip of a strange substance, some kind of horrible acid. Get a drop on you and it takes a massive chunk of health off of you. Time that and get through, and it's Wily again, who suddenly floats in the air and morphs into a friggin' alien! The UFO, the strange technology of the later Wily levels, the ship, it all makes sense! (Well as a kid it did, and heck that's what this game was made for after all.) However he's too strong! He fires the same weapon Megaman started with, but it hurts more and shoots out in all directions. He just flies around a bizarre space dimension in a figure 8, and everything you fire at him seems to bounce off, even the great and powerful metal blades are useless! However, just firing everything you have in the hopes of hurting him, lead bubbles?! Those useless things you took out heat man with? Well, it's unexpected but any shelter in a storm, BAM! You get that pattern down, you bubble him to nothing avoiding everything, you've won! Suddenly the room flashes, Alien Wily suddenly changes to some odd device and you notice a big projector on the ceiling, and turn around to find Wily begging for mercy behind you next to some controls. The whole alien thing was just an illusion, though a powerful one. Wily was just trying to psych you out, lie about his identity, something he'd do again and again in later games, but here you actually bought it. Then, a somber walk through all the seasons (sheesh how long did he WALK?) back home. Credits roll (Fish Man?) and congratulations! Now do it on difficult mode.
On the difficulty, it's not an especially hard game but it does provide good challenge. This game adds E-tanks. These are massive tanks of energy sitting around in hard to reach areas that you can stock up to 4 of. When you are low on health, activate one and get it back to full and you back in the fight. You'll find yourself stocking up 4 of these for Wily's fortress. Certain bosses are harder than others. Start with Metal Man, as cool as he is, he's a pretty easy guy to beat, and the battle's pretty fun too. Air Man, despite the odd music video out there, is also a pretty easy guy, if you have to consume an e-tank on him just get out, get out you failure, I judge you guilty.
Here's a note about the difficulty selection. The Japanese version never had two difficulties. It's difficulty is what you get when you select "difficult" in the US version. In other words "normal" is more accurately called the "easy" difficulty. The main difference is in terms of how many shots an enemy takes before it dies. This does change one enemy's behavior. The giant walking stack of steel containers dies instantly in "normal" and breaks apart, scattering and reforming in a way you have to dodge until it dies in the last shot in difficult.
All in all, an excellent game, and it is little surprise the recent Mega Man 9 game attempted to emulate this more than any other game in the series, even going so far as to eliminate later abilities like the slide and megabuster.
I leave you with this, a tribute to the coolest Robot Master ever (I know many are partial to Skull Man, but this guy wins in my heart, so cool...).